An organization uses Cloud SQL for MySQL in a production environment. They need to ensure high availability with automatic failover in case of a zonal failure. Which configuration should they use?
Regional instances provide a synchronous standby in another zone and automatic failover.
Why this answer
A regional Cloud SQL instance with automatic failover uses a primary and a standby zone within the same region, with synchronous replication between them. If the primary zone fails, Cloud SQL automatically promotes the standby to primary, ensuring high availability without data loss. This configuration meets the requirement for automatic failover during a zonal failure.
Exam trap
The trap here is that candidates confuse cross-region replication (available for other database engines) with the zonal high-availability feature for Cloud SQL for MySQL, or assume that a read replica can be used for automatic failover when it requires manual promotion.
How to eliminate wrong answers
Option A is wrong because a read replica in a different region provides read scalability and disaster recovery across regions, but it does not support automatic failover for the primary instance; failover would require manual promotion, which is not automatic. Option C is wrong because daily exports and manual imports are a backup and restore strategy, not a high-availability solution; it introduces significant downtime and potential data loss, failing the automatic failover requirement. Option D is wrong because Cloud SQL for MySQL does not support cross-region replication for automatic failover; cross-region replication is available for Cloud SQL for PostgreSQL and SQL Server, but for MySQL, it is limited to read replicas, which do not provide automatic failover.